No survivors have been found in the wreckage of two planes carrying 13 people that went missing yesterday in rugged eastern South Africa, a rescue official says.

Johnny Smit, of Rescue South Africa, said wreckage has been spotted from a helicopter in a mountainous area of steep cliffs near Tzaneen, from where the planes left on Sunday for a 250-mile journey to Johannesburg.

Searchers lowered from a helicopter determined the two pilots and 11 passengers - among them two children - had died.

The South African Civil Aviation Authority is investigating the cause of the crash.

Durban Airshow spokesman Ray de Vries said a show organiser was on board one of the two private planes, which both used to be military aircraft.